JP2004259992A - Circuit module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a circuit module so as to reduce the effect of electromagnetic wave noise wherein electronic components are potting-coated with a resin protection body. <P>SOLUTION: In the circuit module, the electronic components 16 are placed on a circuit wiring board 12, the components 16 are connected to an electrode pad 12a of prescribed wire conductors via bonding wires 17, a cylindrical frame 13 is placed to surround the electronic components 16 and the bonding wires 17, and the resin protection body 14 is filled in the frame 13. A shield conductor connected to a ground level is formed to the frame to shut off external noise, and the electronic components 16 are shielded from extraneous noise. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a circuit module having a circuit wiring board on which a plurality of electronic component elements are mounted.
[0002]
[Prior art]
Conventionally, a circuit module has a structure in which an electronic component element mounted on a circuit wiring board is potted with a resinous protection body. For example, a cylindrical frame 37 surrounding the outer periphery of the predetermined electronic component element 34 is attached to the surface of the circuit wiring board 31 as shown in FIG. It was filled and cured with resinous protective material such as resin.
[0003]
Here, FIG. 2A is a perspective view of a circuit wiring board 31 to which a cylindrical frame is attached, and FIG. 2B is a cross-sectional view thereof.
[0004]
Here, the electronic component element 34 covered with the resin protective body 33 can be exemplified by an IC chip or the like. The electronic component element 34 is connected to an electrode pad 36 as a predetermined wiring conductor on the circuit wiring board 31 by a bonding wire 35. The electronic component element 34 is hermetically sealed with a resin protection body 33 obtained by filling and curing a resinous protection material. The resin protector 33 is desirably a gel material having flexibility. For example, when the resin protective body 33 is made of a hard material such as an epoxy resin, when a temperature change is applied, the stress of expansion and contraction of the resin protective body 33 is directly applied to the bonding wire 35, and the disconnection of the bonding wire 35 Peeling of the bonding portion occurs. Therefore, as a material of the resin protection body 33, a gel resin having flexibility, for example, a silicone resin is preferable.
[0005]
However, since the gel-like silicone resin has a low Young's modulus characteristic, in a severe vibration environment such as an engine, a large amplitude due to the resonance of the vibration of the gel-like silicone resin filled in the case or the inside of the cylindrical frame 37 is caused. In addition, there is a problem that a vibration stress is applied to the electronic component element 34 fixed to the circuit wiring board 31 and the bonding wire 35 of the electronic component element 34 containing the gel silicone resin is broken. Therefore, in order to suppress a large amplitude due to resonance at the time of vibration, the filling amount of the resin protector 33 of the gel silicone resin to be filled in the case of the circuit module 30 or the inside of the cylindrical frame 37 is reduced, and the resonance of the gel silicone resin is reduced. Large amplitude can be suppressed. However, when the amount of the resin protective body 33 is small, deterioration due to aging occurs due to intrusion of moisture from the outside, and moisture penetrates into the electronic component element 34 to cause a problem.
[0006]
Further, in the conventional circuit module 30, the crosspiece 32 is disposed on the upper surface of the opening of the cylindrical frame 37.
[0007]
[Patent Document 1]
JP-A-7-231176 [Patent Document 2]
JP-A-2002-246496 [Patent Document 3]
JP-A-2002-299521
[Problems to be solved by the invention]
However, the conventional cylindrical frame has been formed of resin. For this reason, circuit modules mounted on automobiles were sealed in a die-cast (cast) container made of aluminum or zinc, so they were protected from vibration, exhaust gas, dust, etc. Also, electromagnetic noise such as spark noise generated from the air was cut off.
[0009]
However, the function of the circuit wiring board 31 in the circuit module becomes complicated, and a switch circuit or the like through which a large current flows is also included. Even if it is surrounded by the frame 37 and covered with the resin protector 33, noise from the switch circuit through which a large current flows affects the electronic component element 34, which is a small current circuit, through the cylindrical frame 37 and causes malfunction. I will.
[0010]
The present invention has been devised in view of the above-described problems, and has as its object to prevent the influence of noise on an electronic component element covered with a resin protector and to perform a stable operation of a circuit module. Is to provide.
[0011]
[Means for Solving the Problems]
The present invention provides a circuit wiring board on which a predetermined wiring conductor is formed,
An electronic component element mounted on the circuit wiring board and connected by a predetermined wiring conductor and a bonding wire;
A cylindrical frame disposed on the circuit wiring board and surrounding the electronic component element and the bonding wire;
A circuit module comprising a resin protection member that fills the inside of the cylindrical frame and covers the electronic component element and the bonding wire.
The tubular frame is a circuit module having a shield conductor electrically connected to a predetermined wiring conductor having a ground potential.
[0012]
In addition, the cylindrical frame has a cover made of a shield conductor having a plurality of openings and a rib wall protruding toward the inside of the cylindrical frame, which is disposed on an upper surface thereof.
[0013]
The tubular frame is made of a conductive metal member.
[0014]
[Action]
In the circuit module according to the present invention, an electronic component element mounted on a circuit wiring board and covered with a resin protector is surrounded by a cylindrical frame, and further has a flexible gel-like resin protector. Is filled. Further, a shield conductor film that is electrically connected to a predetermined wiring conductor having a ground potential among predetermined wiring conductors of the circuit wiring board is formed on the cylindrical frame. For example, a shield conductor means that a cylindrical frame is formed of a metal member, a shield conductor film is formed on the surface of the side wall of the frame, and a plurality of A cover having an opening and having a rib wall protruding toward the inside of the cylindrical frame is integrated with the cover, and the cover including the rib wall is formed of a metal member.
[0015]
Even when the cover is made of a metal member, it is electrically connected to the ground potential of the circuit wiring board via the side wall of the frame.
[0016]
As a result, the electronic component element is substantially covered with the shield case, so that noise superimposed on the electronic component element can be effectively cut off, and the electronic component element can be operated stably. Become a module.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a circuit module of the present invention will be described with reference to the drawings.
[0018]
FIG. 1A is a plan view of a circuit module showing a first embodiment of the present invention, and FIG. 1B is a side view showing a right half thereof in cross section.
[0019]
The circuit module 10 of the present invention includes an aluminum die-cast housing 11, a circuit wiring board 12, electronic component elements 15, 16, a cylindrical frame 13, a gel-like or It mainly comprises a cured resin protector 14 of a rubber-like resin filling member. The frame 13 shown in FIGS. 1A and 1B is open on the top and bottom, and the lower surface is mounted on the circuit wiring board 12 so as to surround the electronic component element 16. The opening on the upper surface is partitioned by a bar 18 extending vertically and horizontally, and has a plurality of openings. The vertical and horizontal rails 18 serve as a lid of the cylindrical frame.
[0020]
The circuit wiring board 12 includes a board body made of a ceramic or a glass-epoxy material, and predetermined wiring conductors 12a, 12b, and 12c formed on the board body. Electronic component elements 15 and 16 are mounted on such a circuit wiring board 12 and are electrically connected to electrode pads 12 a of predetermined wiring conductors via bonding wires 17.
[0021]
Among the electronic component elements 15 and 16, the electronic component element 15 that does not require the potting of the resin protection body 14 is disposed outside the cylindrical frame 13, and the electronic component element 16 that needs to be covered with the resin protection body 14. Is mounted on the circuit wiring board 12 inside the cylindrical frame 13 and is covered with the resin protector 14.
[0022]
For example, the electronic component element 15 is an electronic component element already covered with a container for improving moisture resistance, an exterior resin, or the like. For example, a trimmer component (variable resistor, variable inductor component, trimmer capacitor, A stub conductor). The electronic component element 16 can be exemplified by an IC chip connected to a predetermined wiring conductor of the circuit wiring board 12 by a bonding wire 17 or various bumps. In the case where the characteristic adjustment is not performed, the electronic component element on which the container or the exterior resin is formed may be arranged in the cylindrical frame 13.
[0023]
The tubular frame 13 is made of an insulating hard resin (for example, epoxy, liquid crystal polymer resin, polycarbonate, PBT, polyamide, polyimide, or the like), rubber, plastic, ceramic, or a metal member. The external shape is a square tubular shape with open upper and lower surfaces. A cover made of bars 18 is provided in a lattice shape on the upper surface or near the upper surface inside the frame 13. The height of the cylindrical frame 13 includes the height up to the highest part of the bonding wire 17 connected to the electronic component element 16, and the height of the cylindrical frame 13 is short. As a result, the overall height of the circuit module 10 can be reduced, and at the same time, the volume of the resin protector 14 is minimized to minimize the stress due to the vibration of the resin protector 14.
[0024]
In FIG. 1, the tubular frame body is formed of, for example, a metal member, and the tubular frame body 13 is mounted on a wiring conductor 12 b formed on the circuit wiring board 12 and having a ground potential. The entire cylindrical frame 13 has a shielding effect. At this time, the electrode pad 12a and the predetermined wiring conductor 12C existing outside the cylindrical frame 13 are connected to the cylindrical frame 13 by forming a wiring conductor inside the circuit wiring board so as not to short-circuit. Just fine.
[0025]
Although not shown, a shield conductor film connected to a wiring conductor having a ground potential may be formed on the outer surface or inner surface of the side wall of the cylindrical frame 13. In this case, the cylindrical frame 13 can be made of an insulating material. Furthermore, if the insulating region is formed on the lower surface side of the cylindrical frame 13, it is not necessary to mount the cylindrical frame 13 on the wiring conductor at the ground potential. At this time, the connection between the shield conductor film and the ground potential wiring conductor is made such that the shield conductor film and the ground potential wiring conductor 12b of the circuit wiring board 12 are connected to a part of the lower surface insulating region of the cylindrical frame 13. The connection conductor film may be formed as described above, and the connection conductor film and the wiring conductor 12b at the ground potential may be electrically connected by a conductive connection member.
[0026]
The resin protection body 14 is formed by filling a predetermined amount of a resinous protection member in an inner region of the cylindrical frame 13 and curing the resin protection member. Examples of the resin protector 14 include low elastic materials such as a gel-like or rubber-like silicone resin and a modified silicone resin. The resin protector 14 has a thickness sufficient to embed at least a bonding wire 17 extending from the circuit wiring board 12 from the electronic component element 16 in the inner region of the cylindrical frame 13, and has an upper surface of a cover 18 serving as a lid. The amount that reaches is the maximum amount.
[0027]
Specifically, various electronic component elements 15 and 16 are arranged at predetermined positions on the circuit wiring board 12, and, for example, after the electronic component elements 16 are connected by bonding wires 17, a predetermined position on the circuit wiring board 12, for example, Then, the cylindrical frame 13 is attached to the ring-shaped wiring conductor 12b having a ground potential corresponding to the shape of the cylindrical frame 13 via a conductive adhesive. Due to the attachment of the cylindrical frame 13, the electronic component element 16 is present in a region surrounded by the cylindrical frame 13. Thereafter, a resin filling member to be the resin protection body 14 is supplied from an opening on the upper surface of the frame 13, and a predetermined amount of the resin filling member is filled in the frame 13. In this way, after supplying a resin-filled member sufficient to bury the electronic component element 16, it is cured.
[0028]
In the case where the cylindrical frame 13 in which the connection conductor film is formed in the lower surface region of the cylindrical frame 13 is used, it is not necessary to attach the connection conductor film to the wiring conductor 12b at the ground potential. Is temporarily held at a position in contact with the wiring conductor 12b at the ground potential of the circuit wiring board 12, and after forming the resin protection body 14, the wiring conductor 12b at the ground potential and the connection conductor film are electrically connected to each other with a conductive adhesive.
[0029]
According to the circuit module 10 formed as described above, substantially only the electronic component element 16 can be covered with the resin protection body 14. At the same time, the filling amount of the resin protective body 14 in the cylindrical frame 13 can be easily controlled, and the curing process and the inside can be easily and quickly confirmed.
[0030]
By curing the resin-filled member, the circuit module 10 can form the stable resin protective body 14 only in a predetermined area for covering the electronic component element 16.
[0031]
The circuit module 10 thus completed is better than the housing 11 against electromagnetic noise in addition to mechanical vibrations from outside the circuit module. Moreover, the electromagnetic noise between the electronic component elements 15 and 16 inside the housing 11 is also excellent because the cylindrical frame 13 has a shielding effect, and the malfunction of the electronic component elements 15 and 16 is reduced. it can.
[0032]
In the above-described example, the structure in which the cylindrical frame 13 itself is formed of a metal member or the main body of the cylindrical frame 13 is formed of an insulating hard resin (for example, epoxy, liquid crystal polymer resin, polycarbonate, PBT, polyamide, polyimide, or the like). A case has been described in which a shield conductor film for achieving an electromagnetic wave shielding effect is formed on the surface of the side wall, made of rubber, plastic, ceramic, or the like. Specifically, the surface of the cylindrical frame 13 is formed by a conductive paint, electroless plating, metal spraying, aluminum evaporation, sputtering, or the like.
[0033]
In addition, a conductive filler, metal powder, and metal flakes may be mixed into the resin forming the cylindrical frame 13.
[0034]
Note that a rib wall may be provided on the lower surface of the bar 18 serving as the lid to protrude into the internal region of the cylindrical frame 13 and partition a part of the resin protection body 14. By doing so, the behavior of the resin protector 14 due to vibration can be reduced, and furthermore, the shield conductor can be arranged near the electronic component element 16, and the vibration stress due to the resin holder applied to the bonding wire 17 can be reduced. In addition, the effect of blocking electromagnetic noise is improved.
[0035]
【The invention's effect】
In the circuit module according to the present invention, since the shield conductor is formed on the cylindrical frame body, the electronic component element is stably protected not only from external electromagnetic noise but also from electromagnetic noise between internal circuit blocks. The circuit module can be operated.
[Brief description of the drawings]
FIGS. 1A and 1B are diagrams showing a circuit module of the present invention, wherein FIG. 1A is a plan view and FIG.
FIG. 2 is a diagram showing a conventional circuit module, wherein (A) is a perspective view and (B) is a cross-sectional view.
[Explanation of symbols]
10. Circuit module 11 Casing 12 Circuit wiring board 13 Cylindrical frame 14 Resin protectors 15 and 16 Electronic component elements 17 Bonding wires 18 Crossbar (lid)

Claims (2)

A circuit wiring board on which a predetermined wiring conductor is formed,
An electronic component element mounted on the circuit wiring board and connected by a predetermined wiring conductor and a bonding wire;
A cylindrical frame disposed on the circuit wiring board and surrounding the electronic component element and the bonding wire;
A circuit module that is filled into the inside of the cylindrical frame and includes a resin protector that covers the electronic component element and the bonding wire,
A circuit module, wherein the cylindrical frame has a shield conductor electrically connected to a predetermined wiring conductor having a ground potential. 2. The circuit module according to claim 1, wherein the tubular frame is made of a conductive metal member.

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